The present invention relates to a wastewater purifying apparatus which can process swiftly and efficiently wastewater containing human excrement discharged from lavatories and the like.
Heretofore, as described, for example, in Japanese Unexamined Patent Publication No. 9-37996, advanced wastewater processing apparatuses that efficiently process wastewater containing human excrement discharged from lavatories or the like by aerating the wastewater in an aeration chamber in the presence of oyster shells as microbial carriers and send the processed water for reutilization as, e.g., flushing water of flush water closets have been known. The advanced wastewater processing apparatus, having an aeration chamber containing microbial carriers made of oyster shell, has advantages in that acidified wastewater can be neutralized by calcium carbonate which become dissolved into the wastewater from the oyster shell, and the wastewater can be purified more efficiently due to increased efficiency of aeration and biological digestion of the wastewater on the surface of the oyster shells.
However, when the oyster shell is used as the microbial carrier in the aeration chamber of the advanced wastewater processing apparatus above, there has been pointed out a problem of a prolonged start-up period, i.e., in that only after a predetermined period from the initial date of operation of the advanced wastewater purification apparatus, the full potential of the apparatus for neutralization and decomposition and purification of the wastewater can be exerted.
In view of the above problem, the present invention has been worked out, and an object of the present invention is to provide a wastewater processing apparatus which does not require a prolonged start-up period and can effectively purify wastewater.
The present invention is directed to a wastewater purifying apparatus having a shell contact aeration chamber placed with microbial carrier shells. Wastewater is fed to and purified in the shell contact aeration chamber. Shells whose mother-of-pearl layer on the inner surface is at least removed are used as microbial carrier. A shell whose porous prismatic layer is exposed owing to the removal of the mother-of-pearl layer on the surface has an excellent function as microbial carrier to be used for purification of wastewater because it has a high affinity to microorganisms and the like which purify wastewater, and it can easily become dissolved into the wastewater.
Additionally, the present invention is directed to a wastewater purifying apparatus further provided with an activated carbon adsorption chamber packed with coal-based activated carbon and arranged downstream of the shell contact aeration chamber. In such an arrangement, treated wastewater purified in the aeration chamber described above is transferred to the activated carbon adsorption chamber where the wastewater is effectively decolorized.
Additionally, the present invention is directed to a wastewater purifying apparatus further provided with a denitrification chamber arranged upstream of the shell contact aeration chamber placed with a bioreactor including a membranous container containing a hydrogen donor. In such an arrangement, ammonia components in the wastewater are converted, via nitrous acid and nitric acid, to nitrogen gas and thus removed from the wastewater by denitrification of denitrifying bacteria adherent to the surface of the membranous container through the use of the hydrogen donor.